David Letterman's rivalry with Jay Leno goes back more than 15 years, to when Leno outmaneuvered Letterman to host the Tonight Show, a job Letterman deeply coveted. Now Leno has ceded the Tonight Show timeslot to Conan O'Brien (rather than fight him from ABC), and accepted to a proffer from network suits to move to 10 pm to make a (still amorphous) show 1/10th the cost of a primetime drama and less likely to be TiVoed. And Letterman isn't about to miss the chance to get in a few digs about how this makes Leno a capitulating loser. (Video after the jump.)

Leno didn't help his case by telling Keith Olbermann that 10:00 is the new 11:30 (included in the video above). Presumably that's the line he'll use when competing with Conan O'Brien for guests!